diff --git a/Data/LHA.lhs b/Data/LHA.lhs
--- a/Data/LHA.lhs
+++ b/Data/LHA.lhs
@@ -106,7 +106,7 @@
 
 ^ Status code of the particle.
 
->   , mothers   :: (Int, Maybe Int)
+>   , mothers   :: MaybePair Int
 
 ^ The mother particles.
 
@@ -147,4 +147,6 @@
 > statusFromInt (2) = IntermediateResonance
 > statusFromInt (3) = DocumentationOnly
 > statusFromInt (-9) = IncomingBeam
+
+> data MaybePair a = PZero | POne a | PBoth (a, a)
 
diff --git a/lha.cabal b/lha.cabal
--- a/lha.cabal
+++ b/lha.cabal
@@ -1,5 +1,5 @@
 Name:                lha
-Version:             0.1.1
+Version:             0.1.2
 Synopsis:            Data structures for the Les Houches Accord
 Description:         This package provides data structures for HEP events, as outlined by the Les Houches Accord (hep-ph/0109068v1)
 Homepage:            https://github.com/bytbox/lha.hs